Why is Milfoil a Threat?

May 24, 2021

Invasive species outcompete the natives. In an organism’s native habitat, its growth is balanced by other organisms that have evolved to compete with or eat it. Invasive plants like variable milfoil are free from their natural competitors and can outcompete native plants for space and sunlight, growing and spreading rapidly, unchecked. Native plants provide both a food source and habitat. When those are altered, invasive plants can drastically alter delicate relationships in the food web. The dense growth and rapid spread of milfoil also dramatically impede swimming and fishing, greatly hurting property values and tourism.

Variable water-milfoil is an extremely hardy perennial. Because it can reproduce by fragmentation, when a disturbance like a motorboat or fishing lure passes through a colony of plants, the chopped-up pieces are each capable of forming a new plant. Milfoil can spread throughout a lake or move from lake to lake on a propeller, trailer, fishing gear or anchor. Photo: Lakes Environmental Association